Pump



Feb. 12, 1929. 1,701,792

"G. F. NELSON PUMP Filed June 2o, 1927 Patented Feb. 12, 1929.

UNiTEn. sierrasV i GEORG-E F. NEISON, OIE' IBEBJKELEfCALIEORNIA.

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Application mea Julie 2o, 192'?. serial No. 199,910.

This invention relates to improvements in vacuum pumps of the type disclosed in j eiiicacy of pumps of this type.

m` pending application for patent liled October 30, 1923, Serial No. 671,725, the primary object being to simplify, reduce in size, render more compact, and increase the One of the objects of the invention is to provide an improved piston or impellerv which is provided with oil seal passages at the contact points thereof whereby oil contained in a chamber provided in the impeller is forced outward between the working surfaces to maintain an oil seal at alltiines,

the construction viding for longer bearings for the impeller shaft than is possible with other types of impellers and thereby improving the pump. l Another object is to provide an improved pum chamber which has a removable end wall that facilitates the maintaining of an oil seal at the joint between the pump cham# ber and said wall and provides for the ready flow of oil into the-pump chamber whereby thorough lubrication of pumpv ,parts is insured.

Another object is to provide an especial pump chamber and impeller constructionl which provides for the escape of gaseous fluid from the pump chamber above the liquid seal level thereby preventing spraying of the liquid into the pump chamber and out of the pump housing with the escaping gase- `ous fluid.

A further object is to provide an im proved shutter having novel adjusting means lproviding for a quick and proper adjustment of the parts in assembling the pump and providing for adjustments to compensate for wear, simple construction, inexpensive, ble in operation.

The pump of the invention is characterized by other improvements made out by the special construction, interrelation, combination and association of various elements thereof wherein the pump as a whole is -inuch more simple as to construction, more compact, consists of fewer parts, is cheaper to make, and'can be operated at less cost to produce a higher vacuum than other pumps of which l am aware.

With .the above mentioned and other objects in view, the invention consists in the novel construction and combination of parts hereinafter described, illustrated in the acand reha.-

of the impeller also proend thereof, is a pump which consists of a substantially cythe shutter being Lof,

companying drawing, and set forth in the claims hereto appended, it being understood that various .changes in the form, proportion, size and minor details'of construction within the'scope of the claims may be re sorted to without departing from the spirit or sacrificing any ofthe advantages of the invention.

Referring to the drawing;

Figxl represents a front elevation of the pump of my inventionwith the side wall of the pump housing and end wall of the pump chamber removed. f

Fig. 2 represents a vertical sectional view taken on the plane of line 2 2 of Fig. 1.

Fig. 3 is a fragmentary perspective view j of the impeller.

The embodiment of the invention shown in detail in the accompanying drawing includesV a housing 1 which in this instance is of rectilinear form andis provided with a removable wall 2. In one wall of the housing is an air intake opening 3 and an air outlet opening 4 into which. are screwed elbow fittings 3 and 4.

Interiorly of the housing at the lower chamber designated 5 and lindrical wall 6 housing 1 and closed formed integral with the on one' end or side by the wall 7 of the housing. The substantially cylindrical or arcuate wall 6 has the upper ends thereof spaced apart a distance, say equivalent to one-fourth of the circumference of said wall, leaving the upper portion of the pump chamber open. rlhe other end or side of the chamber is closed by a removable, slightly resilient plate 8 held against the adjacent edge of the substantially cylindrical-wall 6 by fastenings 8f,`said plate being spaced from the inner side of the removable wall 2 and leaving a space for oil which is contained in the housing. IThis provides an oil seal for4 the jointed parts of the pump.v 'lhe plate 8 is provided with a comparatively large central oi'l 1ntake opening 9, for a purpose which will4 be later described.

A shaft 10 is extended through a bearing 11 in the wall 7 and An impeller or pistonv 14, the peripheral contour of which is of rhomboid-ovate outline is keyed upon the shaft and operates i v within the pump chamber 5, the ends of said mounted on the pin 27 impeller lhaving a working fit with the arcuate Wall 6 of the pump and the parallel sides of the impeller having a similar fit with end Walls of the chamber. This impeller is hollow and provided with a central partition'p15 having a hub sleeve 16 integral therewith. This partition provides chambers 17 and 18 interiorly of the impeller, which chambers communicate with one another through openings 19. The chamber 18 is communicated with the interior of the housing through the opening 9 which is of considerably greater diameter than the shaft 10. Oil contained in the housing 2 will enter the compartments 17 and 18 through the opening 9 and lubricate the bearings for the pump. In this connection it will be noted that the bearings 11 and12 are comparatively long and extend into the compartments 17 and 18. Thus by employing the hollow piston the longer bearings maybe employed and proper lubrication thereof ics insured by oil contained in the chambers into which these bearings extend. A

The contacting ends or faces of the impeller are concentric with the inner surface of the wall 6 for a distance, say approximately one-half inch in length, to provide an effective seal and a working fit of the impeller. To insure proper luirication of the contacting ends of the impeller and to pro. vide an oil seal between these working faces, Oil feed grooves 21 are provided in one side of the impeller so as to conduct oil from the compartments 17 and 18 out onto'the periphery of the impeller. @il forced outward in these grooves by centrifugal force and by pressure against the body of oil contained in the housing passes into oil se'al grooves 21 in the contacting end portions of the impeller thereby providing `the desired oil seal. The periphery of the impeller has substan` tially parallel sides but each end portion is curved with an increasingradii from one side to the otherso that there will be presented on the air discharge side of the impeller a shorter curve than on the opposite side. This ,provides for a comparatively quick rise of the shutter against a slower return thereof and will prevent bouncing of the shutter. This shutter designated 22 is ladjustably and yieldingly held in contact with the periphery of the impeller and with the endv 23 of the arcuate wall of the pump chamber. This shutter is carried on one end of an arm 24 which is mounted on a pin 25, the pin being mounted in an adjustable support 26 which depends from 'a pin 27 projecting from thewall 7 of the housing. The adjustable support 26 is rotatably and is heldin adjusted position by set screws 28. The pin 25 may be raised and lowered on lturning the support 26 on the pin 27. A spring cup 29 is pivoted as at 30 upon the arm 24 and receives thelower end of an expansion s ring 31. The upper end of this spring against a pin 32 extended through a lug 33 which depends from the upper side of the housing, there being a plurality of openings' provided von the wall 7 and said opening' communicates with passages 36 and 37 terminating at their inner ends in openings 38 and 39 which are communicated with the interior of the pump chamber 5 at a point near the end 23 of the arcuate wall of said chamber, the opening 38 being disposed above the one 39 and close thereto; These openings are adapted to be closed bythe sides of the end portions of the impeller as shown in Fig. l, so that when the end por tions of the impeller move downward below said openings, air will be drawn through said openings into the pump chamber by the suction action of said impeller and' produce a vacuum in the passages 36 and 37 withl which the opening 3 and elbow 3 are com` vmunicated. I prefer to employ two openings insteadV of one so that the impeller 'which is at all times bathed in oil, when moving past the upper opening 38 will wipe` oil over the upper opening and thereby remove the oil from the impeller which would otherwise tend to film over the lower opening 39 thusV preventing a lming over of the lower opening and insuring the maintaining of a vacuum. one opening is used, the oil film produced by the impeller wiping over said opening would be maintained 1 throughout the movement of the piston and in some instances would not break down and would therefore prevent a suction or vacuum action being produced by the pump. The two openings prevent this and insure a communication of the exhaust or vacuum line4 with the pump chamber. By having the openings on the side instead of on the arcuate portion of the pump chamber, a more effective sealing of these openings is insured and the destroying of the vacuum by back flow of air is prevented. It will be noted that one end of the arcuate wall 6 of the pump chamber, the end 40, is disposed above the other end 23, said end 40 being above the normal level of oil wit-hin the pump. Thus, as the end of the impeller moves past the end 40, the air carried forward by the piston in the pump chamber is released into the upper part ot' the pump housing above the level of the oil and the tendency of the oil to be forced back past the piston down into the pump chamber is prevented. Air discharged from the pump chamber in this manner passes up and out through the discharge opening 4i. To prevent spraying of oil out of the pump housing` a screen il is provided in the upper part of'the housing as shown in the drawing, this screen extending upwardly vertically in a lateral offset portion 42 of the housing and then downwardly against said offset portion 6, thus providing a double screened wall through which the air must pass before discharging through the opening 4.

The pump is assembled with a suitable quantity of sealing fluid, preferably oil contained therein, the level .of the oil being sufficiently high to seal the joint between the wall 8 and the arcuate wall 6 of the pump chamber but being normally below the upper end 40 of said arcuate wall.

When the pump is used to produce a vacuum, the desired connection is made with the elbow 3 and the pump' set into operation with the impeller turning in a clockwiseia direction.v As the ends of theimpeller move past the openings '38 and 39, air will be drawn into the pump chamber and forced around by the impeller and out between the impeller and the end 40' of the arcuate por` tion of the'chamber into the upper part of the housing 2, from which it passes out to the atmosphere'through the opening t. The

shutter havingl a sealing engagement withthe upper end 23 of the arcuate portion 6 of the' pump chamber fand also with the periphery of the impeller, prevents oil and air from beingdrawn in by the impeller at any point above the openings 38 and 39.

Curving of the ends of the impeller from one side of theJ impeller to the other on increasing radii provides for quicker lifting action than a lowering action of the shutter andl therefore insures anfeti'ective sealing of 'the pump chamber under all conditions of operation, the spring being held effective to l: ,force the shutter into place on the lowering. "'"i'novement of the shutter due to this quickerl action of the shutter.

Oil contained interiorly of the impeller is forced by centrifugal action and pressure on the oil, out through .the small passages 21 into the grooves 21 and provides an oil seal between the working faces of the' impellerl and pump chamber at all times, thereby preventing any escape of air past the impeller back to the exhaust openings 38 and 39.

By having the upper end Li0 of the arcuate ,pump is at rest Vat the periphery ingly held in sealing engagement with the' portion of the `pump chamber disposed above the oil level, when the chamber is at this point, as the impeller moves past said point, the air discharges from the pump chamber wit-hout permitting oil to spray downward past the impeller and into the lower part of the pump chamber.

The wall 7 is provided with a vertical oil groove 7 which extends from a point Vwhere its lower end communicates with the oil compartment ll in the impeller to a point substantially flush with the upper edge of the pump chamber. rl`his groove feeds oil between the working faces of the wall 7 and impeller, also permits oil to tlow upward and into the pump chamber. `When the the norma-l level of the oil is approximately in a plane corresponding to that of the upper side of the intake open-- ing 88, there being ai small quantity of oil contained in the pump chamber on the upper side of the `impeller. in the chamber is forced to the right of the end y4() of the arcuate wall (i at the time of the escape of air between said end 40 and the impeller so that said escape of air -takes place at a point above the level of the oil as previously described.

rllhe pump of my invention may be effectively used as a compression pump as will be obvious on inspection of the drawing and foregoing description. rl`he elfectiveness of the pump for compression purposes is increased due to the as above described. and the effective oil seals provided by this oil and by the construction of the pump itself. rll`hese oil seal provisions prevent all possibility` of leaks and back pressures'and permit of high 'compression of gases with the pump of this invention.

l claim:

1. lua pump' a housing adapted to contain a lubricating fluid and having intake and discharge openings, a substantially cylindrical pump chamber mounted within presence of the oil rlhisoil, however, c

the housing and opening through the up-.

per side of its arcuate wall into` the housing, which chamber is provided through one end `vthe arcuate wall and the end walls vof the chamber, which impeller is provided with Aan oil chamber therein communicating with the oil intake opening of said pump cham-l ber,

said `impeller also having a passage eX- tending from the oil chamber and opemng thereof and a shutter yieldperiphery of said impeller and with one end of the arcuate Wall of the chalnber, the ends of said shutter also engaging the end Walls of the chamber.

2. In a pump a housing adapted to contain a lubricating Huid and having intake and discharge openings, a substantially cylindrical pump chamber mounted Within the housing and opening through the upper side of its arcuate Wall into the housing, which chamber is provided through one end thereof With an intake opening communicating with the intake opening of the housing, said chamber also having an. oil intake opening through one end Wall thereof, a rhomboidovate impeller rotatably mounted Within the lchamber and having a Working t at its ends and on its opposite sides with the arcuate Wall and the end Walls of theA chamber,

which impeller "is provided With an oil chamber therein communicating with the oil` intake opening of said pump chamber, said impeller also having a passage extending from the oil chamber and opening at the periphery thereof and a shutter yieldingly held in sealing engagement with the periphery of said impeller and with one end of the arcuate Wall of the chamber, the ends of said shutter also engaging the end Walls of the chamber, the other end of said arcuate Wall of the chamber being disposed abovel ,the plane ofthe normal level working fit at its ends and on its opposite sides With the arcuate Wall and the end Walls of the chamber, which impeller is provided with an oil chamber therein communicating with the oil intake opening of said pump chamber, said ilnpeller also having a passage extending from the oil chamber and opening at the periphery thereof and a shutter yieldingly held in sealing engagement with the periphery of said impeller and With one end of the arcuate Wall of the chamber, Ythe ends of said shutter also engaging the end Walls of the chamber.

4. A pump comprising a housing adapted to contain oil and having outlet openings, a substantially cylindrical pump chamber provided in the lower portion of said housing and comprising an arcuate Wall closed on one side'by one of the Walls of the housing, a removable Wall closing the other side vofsaid arcuate Wall, said pump chamber hav- 111g an air intake opening extending through their-st named side wall portion thereof, said removable Wall having an oil intake opening therein, a shaft extending into the housing and through the pump chamber, and an impeller mounted on the shaft for rotation yWithin the chamber with its ends in Work- ,ing contact with the arcuate Wall of the chamber and the Sides in workin f engagement with the sides of the chamber, said impeller having an oil chamber interiorly thereof with which chamber said oil intake opening communicates and being provided with an-oil groove leading from\the chamber to the periphery of the impeller and across each endl of the impeller, and a shutter yieldingly held in engagement with the periphery of said impeller and with one end of said arcuate wall of the pump chamber, the ends of said shutter being engaged with opposite walls of said chamber. p l n GEORGE F. NELSON. 

